Am 20.10.21 um 19:43 schrieb Eric W. Biederman:
Reading the history it is unclear why default_trap_handler calls
do_exit. It is not even menthioned in the commit where the change
happened. My best guess is that because it is unknown why the
exception happened it was desired to guarantee the process never
returned to userspace.
Using do_exit(SIGSEGV) has the problem that it will only terminate one
thread of a process, leaving the process in an undefined state.
Use force_sigsegv(SIGSEGV) instead which effectively has the same
behavior except that is uses the ordinary signal mechanism and
terminates all threads of a process and is generally well defined.
Do I get that right, that programs can not block SIGSEGV from force_sigsegv
with a signal handler? Thats how I read the code. If this is true
then
Reviewed-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
Cc: Heiko Carstens <hca@xxxxxxxxxxxxx>
Cc: Vasily Gorbik <gor@xxxxxxxxxxxxx>
Cc: Christian Borntraeger <borntraeger@xxxxxxxxxx>
Cc: linux-s390@xxxxxxxxxxxxxxx
Fixes: ca2ab03237ec ("[PATCH] s390: core changes")
History Tree: https://git.kernel.org/pub/scm/linux/kernel/git/tglx/history.git
Signed-off-by: "Eric W. Biederman" <ebiederm@xxxxxxxxxxxx>
---
arch/s390/kernel/traps.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/arch/s390/kernel/traps.c b/arch/s390/kernel/traps.c
index bcefc2173de4..51729ea2cf8e 100644
--- a/arch/s390/kernel/traps.c
+++ b/arch/s390/kernel/traps.c
@@ -84,7 +84,7 @@ static void default_trap_handler(struct pt_regs *regs)
{
if (user_mode(regs)) {
report_user_fault(regs, SIGSEGV, 0);
- do_exit(SIGSEGV);
+ force_sigsegv(SIGSEGV);
} else
die(regs, "Unknown program exception");
}
